MCAT Biology › Muscle Stimulation and Contraction
What role does calcium play during muscle contraction?
Tests reveal that a certain patient has depleted calcium stores in his sarcoplasmic reticulum. Which of the following is a direct consequence of this abnormality?
Muscle cramps are caused because of prolonged muscle contraction. Prolonged periods of muscle contraction occur because the myosin heads can’t detach themselves from the actin filaments. What is the most likely cause of muscle cramps?
Rigor mortis, a recognizable sign of death, is the stiffness observed in the muscle of an individual who has just passed away. On a molecular level, what causes rigor mortis?
An individual has muscle cells that have an abnormally high level of intracellular calcium. The physician suspects that he may have a genetic defect affecting one of his organelles. Which organelle is likely to be the cause of this condition?
What is the specialized organelle in muscle cells that serves to sequester calcium?
The sarcoplasmic reticulum has the ability to aid in muscle contraction by storing large amounts of which ion?
A weightlifter is trying to increase the force of his muscle contraction in order to lift a heavy weight. Which of the following most adequately explains what is happening in his muscles?
Which of the following proteins binds to calcium released from the sarcoplasmic reticulum?
A muscle will not have all of its fibers contract at once. Instead, the muscle is divided into multiple bundles of muscle fibers, with a neuron innervating all of the fibers in a given bundle. Each collection of fibers controlled by a single neuron is referred to as a motor unit.
Which of the following statements is false when discussing motor units?